A non-formaldehyde alternative to phenol and melamine resins which are based on formaldehyde has been desired because of regulatory and health concerns regarding formaldehyde. Due to the high performance, strength and rigidity of these thermosetting formaldehyde based resins in industrial applications, replacement products maintaining suitable performance have been difficult to find. This invention discloses a resin composition which performs in many applications like phenol-formaldehyde and melamine-formaldehyde resins, but contain no phenol or formaldehyde. These are thermosetting, film-forming compositions which offer tensile strength, rigidity and water-resistance comparable to the phenol-formaldehyde and melamine-formaldehyde resins now in use.
French Patent Application number 94-10186 filed Aug. 22, 1994 by Societe Francaise Hoechst discloses a novel aminoplast resin comprising the reaction product of an amine derivative such as melamine, glycolurile or their mixtures with an aldehyde of the formula R-CHO in which R represents a dialkoxy methyl group, 1,3-dioxolan-2-yl possibly substituted up to 4 and/or 5 times by one or more alkyl groups (preferably up to C.sub.4 alkyl), or a 1,3-dioxan-2-yl group possibly substituted up to 4, 5 and/or 6 times by one or more alkyl groups (preferably up to C.sub.4 alkyl); in mixtures possibly with glyoxal. However, these aminoplast resins do not self-condense satisfactorily, forming films which are weak, brittle and water-sensitive. Attempts to hydrolyze the acetal groups of these resins in order to increase their reactivity resulted in degradation of the melamine ring.
Thus it is an object of this invention to improve the aminoplast resins as disclosed by French Patent Application No. 94-10186 to provide a resin which upon crosslinking provide films which are strong, hard, tough and water resistant. Applications for such improved resins include uses as binders for non-woven substrates such as glass, polyester and nylon fibers used in building materials, air filters or scrub pads, as well as for cellulose substrates such as automotive filters.